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Prawn
05-15-2009, 12:35 AM
I have a scene where a gun is being pointed at someone, then someone tosses something large at the man with the gun. The gun falls from his hand and discharges. How likely is this, and do I need a particular sort of gun for this to work?

Perks
05-15-2009, 12:46 AM
I don't think so. A gun fires when the firing pin taps the primer. I mean, it has to 'tap' it hard, but it is technically possible to fire a bullet from a casing by hitting it just so on a hard object.

I imagine most quality guns are designed not to go off easily, but the fact is, if the mechanism securing the pin gets jostled, accidental discharge is a fact of life.

Scary!

dgiharris
05-15-2009, 12:56 AM
I know some of the older guns don't have safeguards that modern guns have.

Though I can't give you a specific gun (i'm sure some or our NRA bretheren should know :) )

I can give you a scenario that increases the likelihood of an accidental discharge.

Most guns have two modes of firing, double action, and single action.

A double action is usually when a handgun is uncocked. The first pull of the trigger will be at double or tripple the force required to pull the hammer back from the triggering pin.

After the first shot, most guns use a portion of the force to automatically pull the hammer back for the next shot "Single Action". The subsequent shots take less than half the force of the initial shot: Hence the term double and single action.

Ever notice in the movies when the hero cocks his hand gun prior to pointing and shooting. What he is doing is moving his gun from double action to single action.

Same thing happens when the hero uses his thumb to manually pull back the hammer until you here that click. That 'click' is the gun going from double action to single action.

So, when you move your gun from double action to single action (either through cocking the gun or manually pulling back the hammer) you make it a helluva easier to pull the trigger.

Also, there are some people who insist on a 'hair trigger'. This is when they take the gun apart and relieve some of the load on the triggering mechanism (which is extremely ill advised).

If I remember correctly, the double action pull on a 9mm Berrata is 10 lbs of force, so your finger must squeeze with 10lbs of force for the first shot.

The single action pull on a 9mm Berrata is 3 lbs of force.

So, if someone pulls the hammer back and then drops the gun, there is a greater chance of accidental discharge, especially, if said person monkeyed around with the triggering mechanism to get a 'hair trigger'.

But the 9mm has a safeguard that is supposed to prevent this discharge even at single action.

hope this helps some

Mel...

rugcat
05-15-2009, 01:05 AM
The older model S&W 9mm pistols (70's - 80's) were prone to discharging when dropped on a hard surface. I know this from personal experience.

If you google pistol and "accidental discharge" you'll find some useful links.

Prawn
05-15-2009, 02:07 AM
Thanks for the info, everyone! I knew it was possible, I just didn't want to mention the wrong type of gun.

dgiharris
05-15-2009, 02:29 AM
The older model S&W 9mm pistols (70's - 80's) were prone to discharging when dropped on a hard surface. I know this from personal experience.

That must have been a 'fun' experience :)

Mel...

S.C. Denton
05-15-2009, 03:24 PM
An old German Luger(sp?) is your best bet. They required very little pressure on the side of the slides, before they'd fire off an unintentional round. Many German soldiers were consequently wounded due to the malfunction. Which they fixed in later models by switching to a stronger metal for the slides.

You could probably find actual stories about it on the History Channel's website. I imagine they had to have covered this one on Tales of the Gun, though I don't believe that's where I originally saw it. However, it was on one of the History Channel's programs though. But don't take my or their word for it. You could research it much further than that. Perhaps the company has a history of their guns on their website.

TabithaTodd
05-15-2009, 03:34 PM
Any gun does have the potential for accidental discharge. However I would think the older 6 shooters would have more potential for this? Don't quote me though, I'm not sure.

redpbass
05-15-2009, 03:58 PM
I would say any of the cheaply made semiautomatics would be more likely to do this, or guns that have been modified by anyone not a gunsmith.

hammerklavier
05-15-2009, 06:32 PM
Any gun with a free floating firing pin could do this, if dropped on the muzzle! Landing other ways would not effect it. One such gun that was very popular in the 90's and there are still a lot out there is the russian Army 9mm Kurtz Makorov and the popular Bakail knockoff in .380.

WriteKnight
05-15-2009, 06:55 PM
Does it have to be a semi automatic?

The easiest, most likely scenario would be to pick a revolver. You can fire a modern revolver by pulling the trigger - this pulls the hammer back, AND releases it - firing the gun. OR by simply pulling the hammer back - (Using your thumb) - this leaves the trigger in a 'half cocked' position - the lightest pull then releases the hammer.

If the gun were dropped with the hammer cocked, it almost certainly would fire.

(And yes, the 'cheaper' the gun, the more likely it is to misfire.)

Summonere
05-15-2009, 10:23 PM
I have a scene where a gun is being pointed at someone, then someone tosses something large at the man with the gun. The gun falls from his hand and discharges. How likely is this, and do I need a particular sort of gun for this to work?

Short answer: It's your story. If the gun needs to fire when dropped, then make it fire.

How likely is this? It depends. And it probably depends on...

1. Is the gun an old design?
2. Is the gun a modern design?
3. Are the safety systems working properly?

If the answer to #3 is “no,” then almost any gun may fire if dropped. If the answer to #1 is “yes,” then it may well fire if dropped.

For instance, series-70 1911-style pistols can fire if dropped because they don't incorporate the now almost-universal plunger-style firing pin block, and yet this remains a very popular design. Must be tons of them out there. Old style revolvers, like the Colt Single Action Army, with firing pin on hammer, can fire if dropped.

But among modern firearm designs, if the safeties are all working, you'd be hard pressed to make them fire simply by dropping them. They're designed and tested to prevent exactly this kind of accidental discharge. Thus if the answers to 2 and 3 are affirmative, this is likely a no-go scenario.

As to DA/SA pistols and whether or not they'll fire if dropped while the hammer is cocked, the answer is likely no. Modern designs unblock the firing pin as the trigger is pulled.

Don't know much about revolvers, but most modern designs incorporate a hammer block or transfer bar. In either case, the safety block/bar will move to allow firing only when the trigger is pulled rearward to its firing position. This block/bar movement shouldn't occur even if, say, the revolver is dropped on its hammer. Once again, were these bits of gadgetry broken, then you may well have an accidental discharge if the gun is dropped.

More to the point, though, here are some firearms that can fire if dropped.

Dan Wesson 1911-style pistols, series 70.
http://www.cz-usa.com/products_dan_wesson.php

Rock Island Armory 1911-style pistols, also series 70. (And bunches more of this type, by other manufacturers, since it is a widely copied design.)

STI Texican – a copy of the Colt SAA
http://www.stiguns.com/guns/Texican/Texican.html

Ruger LCP (pre recall)
http://www.ruger-firearms.com/LCPRecall/index.html

Ruger SR9 (pre recall)
http://www.ruger-firearms.com/SR9Recall/

Many more are listed at this site...

http://www.firearmsid.com/Recalls/FA_Recalls%202.htm

...including...

BRYCO ARMS
MODEL 38,
380 AUTO CALIBER SEMI-AUTOMATIC PISTOL

COLT
MODEL JUNIOR COLT,
25 AUTO CALIBER, PISTOL

COLT
380 AUTO CALIBER, SEMIAUTOMATIC PISTOL

COLT
MODEL ALL AMERICAN,
9MM LUGER CALIBER, PISTOL

C.O.P.
MODEL “COP”,
357 MAGNUM CALIBER, 4 BARRELED PISTOL

P.S. Good luck with Akiva.

Maiden
05-16-2009, 12:59 AM
Single action army revolvers will. Some of the old German pistols (WW2 era or older) would go off if you sat on them. Colt model 1911 and single action revolvers will if the hammer is down on a live round. No double action handgun, or Ruger model, will go off if dropped though because they have a transfer bar. No Ruger firearm will because it has a transfer bar.

On the single action army and Colt model 1911 it is pretty likely that it go off it dropped.

Above information credited to my husband who is a gun collector, and firearm history buff.

Chase
05-16-2009, 01:42 AM
Summonere,

Excellent answer to Prawn’s writing problem. Your thoughtful answer and research put the guessers to shame. The only gun ban I favor is a ban on those not knowing jack from giving advice about them.

On the single action Texican you mentioned. It’s a good knockoff of the Colt single action army. Whether they will go off if dropped while cocked is iffy. But as you said, if the writer wants it to happen, then it’s certainly possible.

However, the Texican, third-generation Colt SAAs, and the old three-screw Ruger Blackhawk will fire if dropped on the hammer spur if the hammer is completely down on a loaded chamber (not quarter- or half-cock, although those positions have their separate safety issues).

Maiden's hubby is correct on two-screw Rugers -- or those having been converted to a tranfer bar by Ruger.

That’s why all ald cowboys and those who participate in cowboy competition only carried five cartridges in a six-shooter – so that an empty chamber was under the hammer.

The problem these guns present the writer is even with all six chambers full, they are not ready to fire if the hammer is down. However, I note the gun was merely pointed by the character, not necessarily ready to fire.

I know, details always seem to beget more details, but the writer has committed himself to be accurate, and you did a terrific job of offering expert helps. In this case, methinks a single action oldie isn’t the best candidate for an oops discharge.

Chase, an old wheelgunner

Maiden
05-16-2009, 01:54 AM
I am not a Good transciptionist... My husband likes to talk about guns so when I asked him I had to try and pick out information from the outpouring.

But to answer your original question you wouldn't have to name a specific gun if you didn't want too since there are several that could go off if dropped. If you are just calling the gun a gun you should be fine. I

Prawn
05-16-2009, 02:07 AM
Thanks so much for all of the answers! I am humbled by the expertise displayed by you guys. I think I will go with a revolver. The story is modern, so many of the colts and six shooters wouldn't fit. I don't know much about guns, but I bet if I made a silly mistake such as choosing the wrong gun, it would cause a gun enthusiast to stop reading. And if an editor happens to be a gun enthusiast...

Thanks again folks!

hammerklavier
05-16-2009, 05:38 PM
You need to go to a firing range that offers handgun courses and enroll, you can rent a gun there if you don't have one. It'll do wonders for your writing of gun scenes.

Summonere
05-16-2009, 10:25 PM
Chase:

Thanks for the info about revolvers. Aside from my other deficiencies of knowledge, wheel guns remain a big one. Grew up shooting an old .22 Colt Peacemaker and, later, a Ruger .454 Super Redhawk. Never took those apart, though, as they weren’t mine.

Of course if the gunman in Prawn’s story is toting, say, a Glock or S&W M&P, drops it, and something were to slip into the trigger guard and engage the trigger in such a way as to defeat the trigger safety, ka-pow!

Meanwhile…

Found these animations by Googling about the Internet, so there‘s no telling what else is on these sites. Nonetheless, they may answer a few questions or curiosities about how some of these gadgets work.

1911-style pistols:

http://www.truveo.com/Colt-1911-CutAway-Animation/id/3271554035

http://www.m1911.org/loader.swf

(The above seems to be the same as, or at least very similar to, the STI screensaver download over here: http://www.stiguns.com/ )

1911-style pistol reassembled from detail-stripped condition.
http://video.google.com/videoplay?docid=-5053379821405436208

Glock:
http://www.sniperworld.com/glock/
http://www.sniperworld.com/content.aspx?ckey=Sniper_World_Glock_Index

Revolver (looks like a firing-pin-on-hammer animation):
http://static.howstuffworks.com/flash/revolver-diagram.swf

Pistol/Revolver -- lots of other info, here, too (accessible from main site).
http://www.genitron.com/basics.html

Hope these links prove useful (though they don’t answer the original question : ).

P.S. More good luck on Akiva, Prawn.

Rowan
06-11-2009, 03:36 AM
I have a scene where a gun is being pointed at someone, then someone tosses something large at the man with the gun. The gun falls from his hand and discharges. How likely is this, and do I need a particular sort of gun for this to work?

I was going to say -- a SIG SAUER would never do this... But a Glock? YES! Can you tell that I don't like Glocks? :tongue Glocks are single action (SA) handguns and require very little trigger pull to discharge a round (I know from personal experience carrying/firing a Glock). If someone threw something at your character, he could easily 'startle' and let off a round w/out dropping it (maybe just before dropping it?). That might solve your problem. Keep in mind - that would be hard to do with a DA/SA weapon like a Sig, Hechler & Koch (and those listed by the previous posters) unless the hammer was cocked or a handgun w/a safety mechanism like a Kimber, etc.

Smiling Ted
06-11-2009, 08:30 AM
A good bet is a cheap .22 or .25 semiautomatic pistol made by one of the "Ring of Fire" companies - Raven, Bryco, Jimenez, Jennings. They have a rep for misfiring and worse.

Richard White
06-11-2009, 11:36 PM
I know from repeated personal experience that an M-16 will discharge if the butt of the stock is dropped onto a hard surface (like the tile floors of a barracks).

Luckily for all involved, the rifle was loaded with blanks, but it happened both at Ft. Campbell and at Ft. Bliss after field exercises with (supposedly) cleared weapons.

Sigh

(I realize this isn't a handgun, but wanted to show even rifles were not immune to accidental discharge if a round is in the chamber.)

AceTachyon
06-12-2009, 12:56 AM
For instance, series-70 1911-style pistols can fire if dropped because they don't incorporate the now almost-universal plunger-style firing pin block, and yet this remains a very popular design. Must be tons of them out there.

I thought the grip safety prevented that?

Or is the grip safety a later feature? I know mine has one in addition to the slide safety.

Billytwice
06-12-2009, 01:25 AM
WW2 Sten guns will go off if you look at them the wrong way...they were mass produced and would empty their mags if jostled, I've heard they shot the arms off several soldiers on exercise.

Chase
06-12-2009, 03:07 AM
I've heard they shot the arms off several soldiers on exercise.

Billy, Billy. We've all heard these barracks stories, but since serious writers rely on facts to base their fancy, can you find even one single documented case of a handgun or rifle ever shooting off an arm? Just one?

Anyone?

Bueller?

Anyone?

No? That's because it's never happened.

Summonere
06-13-2009, 02:10 AM
I thought the grip safety prevented that?

Or is the grip safety a later feature? I know mine has one in addition to the slide safety.
The series-70 1911s -- ones without a firing pin block -- are the ones that can discharge, if dropped. Condition 2 carry is the most likely scenario, which would have a live round in chamber, hammer down, safety off. In such case, a sufficiently sharp blow against the hammer could conceivably cause a discharge by spanking the firing pin straight into the live primer.

In order to get a cocked-and-locked series-70 1911 to fire if dropped, something would have to break. If the sear hook broke off the hammer when dropped, or the sear itself broke, or both of them broke, the hammer could fall and the gun could fire. The thumb safety, even while applied, would not stop the hammer from falling in these scenarios. It would, however, prevent the gun from firing more than once. If, however, the thumb safety were not applied and the above-mentioned gadgets broke when dropped, the pistol could, conceivably, keep firing until it expended every round in the magazine.

Series-80 versions of the 1911 design incorporate a firing pin block that, in the above drop-and-break scenarios, would simply keep the firing pin blocked, preventing the pistol from firing at all. And since the trigger pull is necessary to unblock the firing pin in this design, and since the grip safety must be depressed in order to pull the trigger (that goes for both versions of the design), the odds are very slim for series-80 pistols to fire if dropped.

As to the grip safety and was it a later feature, the answer is a qualified yes. The original design didn't incorporate one, but since the U.S. Army insisted upon additional safety for an instrument of war (ironic, that), John Browning added one.

Those things said, the 1911 remains an excellent design.

Todd Bayliss
06-16-2009, 01:15 AM
Ruger LCP

(just recalled because of this)